# The metric system: Make your case for it and why we should switch to it. (As if we haven't already)

In that case… our destination is 30 Patriots distant, it is half past two o’Freedom, and the temperature is 72 Eagles.

This sounds like a line uttered ironically by Kurt Russell in an un-produced Escape from Seattle movie.

Stranger

If your gal is glowing, you can measure her radiance at a given wavelength using an optical pyrometer via Planck’s law. Therefore, the answer in that case is neither, but rather Kelvins or, more accurately, thermodynamic beta.

If only there were scales that measured in ounces … oh wait, there are.

You’re from SoCal, right?

Yes, but still, 0C is common out here. -18 C? rare, except on top of mountains.

It is far more common to see 0C than -18 C, or 32F vs 0F.

In F, “temps below freezing” means really fucking cold, take serious measures if going outside. Protect water pipes and such.

In C, “temps below freezing” means wear a warm sweater.

Wake me up when this is settled.

Just please don’t force me to start saying “K” for thousand. Ooh, I hate that! (Yosemite Sam voice)

Unfortunately, almost all US recipes use volumetric measures for both dry and liquid ingredients. It’s not that you can’t use ounces (though don’t get confused with the fluid ounce)… it’s just not done. European recipes are much more likely to use grams for dry ingredients.

Sure but that’s got nothing to do with metric. It’s that for whatever reason, US recipes use volume, not weight.

I agree; it’s just a weird habit we picked up and never broke. Like the power-of-2 divisions of the inch.

Question for Chefguy - or for anyone - do European recipes say “four eggs”, or “200 grams of egg”, precision being such a highly-prized commodity, and eggs do vary?

I cook like the Swedish Chef. Throw it all together, and if it comes out a hockey puck, you eat it anyway.

That would be something. Imagine seeing a sign that said “Maximum Speed 480.” Which is what 60 mph would be in furlongs-per-hour.

And to make it real fun, the fine for going 500 furlongs could be levied in pre-Euro liras!

“That’ll be 100,000 liras!”

4 * 5 = 20
3 * 2 = 6
20 + 6 + 1 = 27/32

Nothing to it.

I didn’t say it was impossible. Are you seriously arguing against the point I was making - you’re claiming that it’s just as easy?

Not always, but that example certainly was.

That’s just not a credible claim. You’ve spelled out the fact that additional complexity is involved in conversion to a common denominator.

@SCAdian demonstrates both sides of this point.

For folks who routinely deal with measurements like x/2n for small integer x and small n like that, it becomes an embedded automatic skill to make those types of conversions without “really” doing mental math. You just look at 5/8 and “see” 20/32. You look at 3/16 and “see” 6/32. So almost without effort and certainly without conscious calculation the equation turns into 20 units + 6 units + 1 unit. Now you perform the math yielding 27 units. Finally you take notice that units is /32s and you write the answer: 27/32.

Conversely, somebody who does NOT do these sorts of conversions in their head regularly is facing the prospect of firing up their rusty algebra, deciding how to solve this higher math conundrum, then chugging laboriously through finding a lowest common denominator, converting two of the three fractions to it, adding up, then, if possible and necessary, simplifying. Whew; I’m exhausted.

For darn sure adding decimal fractions skips the LCD conversion step. On the other hand, for e.g. 1.2 + 0.5 + 0.002, you’re doing floating point addition, not integer addition. And just like inside a computer, there’s opportunities to get the exponents wrong. Quick, does my example add up to 1.72 or 1.702? If I throw a couple more significant leading zeros in there it gets trickier.

In my job we’re often converting between hours:minutes and hours.hundreths. There’s a few other angular math problems not involving time but also involving a divisor of 60. It’s almost unconscious for me to do that stuff now. It doesn’t “feel” like arithmetic. It feels more like a table lookup, akin to what “5 times 6” feels like to most educated adults.

I’m not defending the wisdom of x/2n over decimal. Just pointing out that humans get good at whatever mental math they practice. Some of us get real good. Whatever calcs you (any you) practice regularly may well be easier for you than other calcs that are objectively simpler.